Roller adjusting apparatus for a proof press

ABSTRACT

An apparatus for positioning the pressure roller of a printing machine to control the pressure exerted on a record material and an inked artist&#39;&#39;s plate on which the record material is positioned. A jackscrew horizontally displaces a tapered block which in turn exerts a vertical force on a second tapered block. The second block is attached to the shaft of the pressure roller and transmits the vertical force to the pressure roller.

United States Patent [72] Inventor Kenneth W. Cohen 1,668,616 5/1928 Tracy 101/23 11258 Walnut Ridge, Chesterland, Ohio 2,719,483 10/ 1955 Smith 101/247X 44026 2,967,477 l/l96l Ritzerfeld..... 101/91X [2]] Appl. No. 757,425 3,455,236 7/1969 Lewis 101/23 [22] Filed Sept. 4, 1968 FOREIGN PATENTS 1451 1971 846,401 8/1952 Germany 101 247 789,272 7/1968 Canada 101/247 [54] ROLLER ADJUSTING APPARATUS FOR A PROOF P i E i R b 1 E. Pulfrey PRES S Assistant ExaminerC. Coughenour 6 Claims, 2 Drawmg Figs. Attorney-Michael P. Lynch [52] US. Cl 101/250, 72/243,72/248, 100/168, 101/282 [51] Int. Cl B4lf 3/28 [50] Field of Search 101/ 247, ABSTRACT; An ap aratus for positioning the pressure roller 243, of a printing machine to control the pressure exerted on a 244, 248 record material and an inked artists plate on which the record material is positioned. A jackscrew horizontally displaces a [56] References cued tapered block which in turn exerts a vertical force on a second UNITED STATES PATENTS tapered block. The second block is attached to the shaft of the 810,016 1] 1906 Wood 101/282X pressure roller and transmits the vertical force to the pressure 1,423,792 7/1922 Gowdy l0l/349X roller.

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ROLLER ADJUSTING APPARATUS FOR PROOF PRESS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a roller positioning apparatus of a proof press and more particularly to a positioning apparatus which exerts a vertical roller pressure proportional to the setting of a horizontal jackscrew.

2. Description of the Prior Art The printing machine, generally classified as a proof press, is a machine capable of exerting extreme pressure over the surface of an artist's plate. Generally, the proof press is one of two types: a single roller machine in which the roller acts against a stationary bed plate or the more conventional dual roller machine in which the bed plate and artist's plate pass between the pair of rollers.

The roller adjust apparatus commonly used to control the pressure consists of a vertically positioned jackscrew exerting a vertical force on the adjustable roller. This arrangement has produced several undesirable results, including rapid wear of the jackscrew and inability to accurately control the position of the adjustable roller.

SUMMARY OF THE INVENTION A proof press utilizing a horizontal adjustment to accurately control the vertical pressure applied by said pressure roller to an artist's plate. The horizontal adjustment provides a reliable and durable method of adjusting pressure roller position. Furthermore, the design of the proof press which is the subject of the invention provides structural support members which exhibit sufficient spring rate so as to compensate for mechanical variations in the pressure roller or artist's plate which could otherwise result in uneven printing pressure across the artist's plate.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of the preferred embodiment of the invention.

FIG. 2 is a sectioned view of prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, there is illustrated in FIG. 1 a contact printing machine classified as a proof press, consisting basically of frame 1, reference roller 8, pressure roller 12, pressure adjusting apparatus 13 to control the positioning of pressure roller 12 with respect to reference roller 8 and drive system 43 which causes pressure roller 12 to rotate and draw the inked image plate 54 and record material 55 between the roller surfaces. The basic construction of the printing machine herein illustrated forms no part of the present invention; and, since printing machines of this type are well known in the art, it is believed that a detailed description of the machine and its operation is unnecessary for complete understanding of the invention.

The apparatus which controls the positioning of pressure roller 12 relative to reference roller 8 and which forms the invention as defined in the appended claims consists of duplicate sets of apparatus 13 and 130, one set associated with each end of pressure roller 12. Inasmuch as the arrangement of each set of apparatus and the operation of each set of ap paratus is identical, for the purpose of clarity, the discussion will be limited to apparatus 13 which is clearly illustrated in the drawing.

Reference roller 8 is mounted in frame 1 and is free to rotate in bearing assembly 10. Pressure roller 12 is suspended in a position directly above reference roller 8 by support arm 15. Shaft 14 of pressure roller 12 is inserted in a bearing assembly in one end of support arm 15, and the opposite end of arm 15 is pivotally attached to pin 16 in frame I. The vertical movement of pressure roller 12 provided by the pivotal connection of arm 15 is biased by the counteracting influence of tension spring 22.

Adjusting apparatus 13 is essentially comprised of tapered force block 17 which is slideably positioned against surface 34 of frame member 6 by threaded jackscrew 26. The tapered surface of force block 17 coacts with the tapered surface of reference block 18 to exert a vertical force on pressure roller 12. Reference block 18 is pivotally connected at pin 19 of force arm 20 such that surface contact between the tapered surfaces of force block 17 and reference block 18 is not of fected by vertical pivotal-motion of pressure roller I2.

The positioning of pressure roller 12 with respect to the surface of reference roller 8 is extremely important in that it establishes the vertical roller spacing 28 through which bed 52 and the inked artist's plate 54 and record material 55 will pass during the printing operation. Since the roller pressure applied to the print material positioned on bed 52 is controlled by the vertical positioning of pressure roller 12, the quality of the print is directly related to the degree of control provided by adjusting apparatus 13.

A typical prior art pressure roller adjusting apparatus is illustrated sectionally in FIG. 2 of the drawing and it is identified as Prior Art. Reference roller 102 is mounted in frame 104 for rotation about shaft 105. Pressure roller I06 is mounted in bearing cage and positioned vertically in slot 111 by jackscrew 108. The vertical adjustment of jackscrew 108 controls the vertical spacing between the surfaces of reference roller 102 and pressure roller I06. Positioning of pressure roller 102 with respect to reference roller I06 con trols the pressure applied to the art work placed on bed [12 and passed between rollers 102 and 106. The control of pres sure roller vertical position and consequently the ultimate roller pressure is, at best, coarse when the adjusting apparatus illustrated as Prior Art is utilized. The direct contact between jackscrew 108 and roller bearing cage 110 results in rapid wearing of the jackscrew. Furthermore, the limited load bearing contact area existing between the roller bearing cage "0 and jackscrew 108 produces unacceptable stresses which result in premature fatigue failure. These undesirable design features of the Prior Art roller adjusting apparatus, which have thus far been commercially tolerated, are overcome by adjusting apparatus 13 heretofore described.

As noted previously, the jackscrew adjustment 26 of the apparatus 13 does not directly apply a vertical positioning force against pressure roller 12; rather, it horizontally displaces force block 17. Pivoted reference block 18, which is connected to vertical force member 20 in a position directly above roller shaft 14, is maintained in contact with force block 17 by the action of tension spring 22 which is connected between support arm 15 and frame member 6. The substantial surface contact maintained between force block 17 and frame sliding surface 34, as well as between the tapered surfaces of force block 17 and reference block I8, substantially reduces the stresses encountered in the Prior Art design.

T-track 24, in addition to functioning as a guide track for the horizontal movement of force block 17 against frame surface 34, cooperates with set screws 36 and 38 to prevent disassociation of force block 17 from frame member 6 when force block 17 is displaced by jackscrew 26 to a position at which contact between blocks 17 and 18 is no longer sufi'icient to maintain block 17 in contact with frame surface 34. In the event of this extreme condition, wherein the vertical force applied to the tapered surface of block 17 by block 18 is insufficient to maintain force block 17 contact with surface 34, force block 17 will lower until screws 36 and 38 contact the horizontal member of the T-track. Force block 17 will remain in this position until jackscrew 26 establishes a force block position which is within normal control limits.

Furthermore, the disassociation of the jackscrew 26 from the direct contact configuration displayed in the Prior Art increases the useful life and improves the overall reliability of the jackscrew 26 by reducing the rate of wear. The uniform and sensitive control of the vertical position of pressure roller 12 provided by the horizontal jackscrew 26, and the mechanical advantage inherent in the arrangement of tapered block 17 and 18, enable operator control of the roller pressure applied to art work which isfar more precise than available in the Prior Art design.

The tapered block arrangement, in addition to the advantages heretofore described, provides a self-locking feature in the form of the locking angle defined by the coefficient of friction between the tapered surfaces of force block 17 and reference block 18. This feature insures repeatable roller positioning and substantiates the validity of the roller position indicated on scale 42 by pointer 40.

The pressure roller adjusting apparatus 13 and the duplicate apparatus 13a provide independent control of the position of the respective ends of pressure roller 12 with respect to reference roller 10, and, therefore, permit the operator to regulate the pressure applied to the artist's plate 54 and record material 55 so as to compensate for variations in the inked image.

Compensation for plate and roller irregularities is provided by the inherent spring rate of frame member 6. This inherent capability of the frame structure to absorb a change in roller pressure resulting from slight mechanical irregularities results in a printing pressure which is far more uniform than that provided by the Prior Art designs.

It will be apparent to those skilled in the art that many clanges may be made in the construction and arrangement of parts without departing from the scope of the invention as defined in the appended claims.

lclaim:

l. A proof press for transferring the inked image from an artist's plate to a sheet of suitable record material, said printing press comprised of:

a support frame;

a rotatable reference roller mounted in said frame;

a rotatable pressure roller;

pivotal arms connecting either end of the shaft of said pressure roller to said frame, said arms pivoted at the frame connection and extending horizontally to the ends of said pressure roller shaft;

horizontal adjusting means associated with either end of said pressure roller shaft to adjust the vertical distance between the pressure roller surface and the reference roller surface;

resilient means extending from said pivotal arms vertically to a horizontal frame member and acting in tension to maintain contact between the adjusting means and the ends of the pressure roller shaft;

drive means connected to said pressure roller to rotate said roller and draw the inked artist's plate and record material between said rollers causing the roller pressure exerted against said plate and record material to produce an inked print on said record material;

wherein said horizontal adjusting means associated with the ends of said pressure roller is comprised of a first and second force transmitting member, said first member attached to one end of said pressure roller shaft and extending vertically therefrom, said second member attached to the other end of said pressure roller shaft and extending vertically therefrom;

a first and second tapered reference block, said first reference block pivotally connected to the first transmitting member and said second reference block pivotally connected to the second transmitting member;

a first and second tapered force block slideably positioned against the horizontal frame member the tapered surfaces of said force blocks coacting with the tapered surfaces of said reference blocks to exert a vertical force on the ends of the pressure roller shaft, said force being a function of the horizontal position of the force block, suid force being in opposition to the force established by the resilient means which maintains the tapered surfaces of each pair of force and reference blocks in mechanical contact and the force blocks in turn in contact with the horizontal frame member; and l means for independently ad usting the horizontal posrtlon of each force block and thereby permitting the pressure roller ends to be adjusted to different heights with respect to the surface of the reference roller.

2. A proof press as claimed in claim 1 wherein said means for independently adjusting the horizontal position of said force blocks is comprised of: a first and second threaded rod each having a handle, said first rod passing horizontally through said frame and threaded through said first tapered force block, the rotation of said rod causing said force block to be horizontally positioned against the frame and the corresponding reference block, said second threaded rod passing horizontally through said frame and threaded through said second tapered force block, the rotation of said second rod causing said second force block to be horizontally positioned against the frame and the corresponding reference block.

3. A proof press as claimed in claim I further including an indicating means responsive to the horizontal movement of said force block and representing the movement of said block in terms of the height of the pressure roller above the reference roller.

4. A proof press as claimed in claim 3 wherein said indicating means consists of a scale and pointer combination wherein the scale is affixed to the horizontal frame member against which the force block is positioned and the pointer attached to the slideable force block.

5. A proof press as claimed in claim I further including a guide track connected to the frame surface against which the force block is positioned and extending horizontally along said frame member to prevent the force block from losing contact with the frame member when the force block is positioned out of range of the reference block by the horizontal adjusting means.

6. A proof press as claimed in claim I wherein said support frame includes structural means for supporting the pressure roller adjusting means, said structural means exhibiting a spring rate of sufficient magnitude to compensate for mechanical variations in the pressure roller or artist's plate and thereby maintain uniform printing pressure on the artist's plate. 

1. A proof press for transferring the inked image from an artist''s plate to a sheet of suitable record material, said printing press comprised of: a support frame; a rotatable reference roller mounted in said frame; a rotatable pressure roller; pivotal arms connecting either end of the shaft of said pressure roller to said frame, said arms pivoted at the frame connection and extending horizontally to the ends of said pressure roller shaft; horizontal adjusting means associated with either end of said pressure roller shaft to adjust the vertical distance between the pressure roller surface and the reference roller surface; resilient means extending from said pivotal arms vertically to a horizontal frame member and acting in tension to maintain contact between the adjusting means and the ends of the pressure roller shaft; drive means connected to said pressure roller to rotate said roller and draw the inked artist''s plate and record material between said rollers causing the roller pressure exerted against said plate and record material to produce an inked print on said record material; wherein said horizontal adjusting means associated with the ends of said pressure roller is comprised of a first and second force transmitting member, said first memBer attached to one end of said pressure roller shaft and extending vertically therefrom, said second member attached to the other end of said pressure roller shaft and extending vertically therefrom; a first and second tapered reference block, said first reference block pivotally connected to the first transmitting member and said second reference block pivotally connected to the second transmitting member; a first and second tapered force block slideably positioned against the horizontal frame member, the tapered surfaces of said force blocks coacting with the tapered surfaces of said reference blocks to exert a vertical force on the ends of the pressure roller shaft, said force being a function of the horizontal position of the force block, said force being in opposition to the force established by the resilient means which maintains the tapered surfaces of each pair of force and reference blocks in mechanical contact and the force blocks in turn in contact with the horizontal frame member; and means for independently adjusting the horizontal position of each force block and thereby permitting the pressure roller ends to be adjusted to different heights with respect to the surface of the reference roller.
 2. A proof press as claimed in claim 1 wherein said means for independently adjusting the horizontal position of said force blocks is comprised of: a first and second threaded rod each having a handle, said first rod passing horizontally through said frame and threaded through said first tapered force block, the rotation of said rod causing said force block to be horizontally positioned against the frame and the corresponding reference block, said second threaded rod passing horizontally through said frame and threaded through said second tapered force block, the rotation of said second rod causing said second force block to be horizontally positioned against the frame and the corresponding reference block.
 3. A proof press as claimed in claim 1 further including an indicating means responsive to the horizontal movement of said force block and representing the movement of said block in terms of the height of the pressure roller above the reference roller.
 4. A proof press as claimed in claim 3 wherein said indicating means consists of a scale and pointer combination wherein the scale is affixed to the horizontal frame member against which the force block is positioned and the pointer attached to the slideable force block.
 5. A proof press as claimed in claim 1 further including a guide track connected to the frame surface against which the force block is positioned and extending horizontally along said frame member to prevent the force block from losing contact with the frame member when the force block is positioned out of range of the reference block by the horizontal adjusting means.
 6. A proof press as claimed in claim 1 wherein said support frame includes structural means for supporting the pressure roller adjusting means, said structural means exhibiting a spring rate of sufficient magnitude to compensate for mechanical variations in the pressure roller or artist''s plate and thereby maintain uniform printing pressure on the artist''s plate. 